What is fracking?
Jenna Brown, a first year PhD student, started off with an introduction to fracking, or hydraulic fracturing.
Gas molecules trapped in dense shale rocks are almost impossible to obtain by normal drilling. Fracking involves drilling vertically down and then horizontally into the rock. Fracking fluid, a mixture of water, sand and other chemicals, is injected into the rock at high pressure, expanding the tiny cracks and allowing the gas trapped within to escape and travel back up the pipe for collection.
|Taken from BBC News|
Natural gas is viewed as a transition energy source from dirty fossil fuels to greener renewable energies in the future. It produces almost half the amount of carbon dioxide per unit of energy than coal, which could help us meet the national target of reducing CO2 emissions by 80% by 2050.
|Image by Varodrig|
Jenna explained that the government see shale gas as a way to improve our national energy security. The British Geological Survey estimates that the Bowland Shale reserve in central England holds 1329 trillion cubic feet of shale gas, although across the entire UK estimates vary wildly because they are mainly based on data from other countries. Jenna highlighted the fact that whilst this is a huge amount of fuel, much if not most of it will not be technically recoverable. Still, it could provide greater energy security in the UK, which imported one trillion cubic feet of natural gas in the first six months of this year.
Dr. Chad Staddon, associate professor of resource geographies at UWE, spoke about the possible problems that UK water security faces with fracking. As well as the potential to pollute ground water (explained here), Chad was concerned that fracking could pose a problem to UK water security but even more worried that this had not yet been assessed in detail.
Fracking requires a huge volume of water; around 4 - 20 million litres per well in the USA according to the International Energy Agency. This amounts to just 0.3% of US national water usage, however Chad highlighted two important problems with this figure. First, US shale reserves are only around 750m deep. In the UK, our reserves may reach down as far as 3km, meaning we could layer six or more horizontal fracking pipes in a single well. The increased depth and number of fracking pipes means that significantly more water may be required in UK sites.
The second issue is one of local resources. Even in relatively rainy countries there can be pockets of water scarcity, which can be intensified by local demand. Unfortunately, there is little guidance in the published scientific literature to aid the UK in avoiding over-committing our water to fracking at the cost of food production and water security. Parts of the UK, such as the south east, are already at water capacity. Adding the water demands of fracking may lead to local droughts or the costly transport of water from other parts of the country. A 2013 report for the Department of Energy and Climate Change stated that if waste water is recycled where possible, water requirements for fracking could be managed sustainably.
|Methane emissions in the USA.
Image from United States
Environmental Protection Agency
Dr. Enda Hayes, a UWE research fellow, spoke about the effect fracking could have on air quality management. He was trying to learn more about the emissions from a shale gas well, however the findings in scientific reports varied enormously because no two wells are the same. Different geographies, demands and outputs greatly affect the results, which means that it is very difficult to use US data to try and predict the effect of fracking on UK air quality. Fracking could contribute to particulates and toxic compounds in the air, as well as increased CO2 emissions and methane leaks.
Less CO2 is produced per unit of energy when burning shale gas compared to coal and oil. However Enda spoke about recent reports stating that the net effect of shale gas on greenhouse gases is likely to be small, and could actually increase emissions if the displaced coal and other fossil fuels are used elsewhere. Another major player in climate change is methane. In the USA, 11% of methanee missions are produced from coal mining, mainly by methane leaking from the mines. Shale gas is mostly comprised of methane, which must be properly contained to prevent even greater emissions from leaks.
The panelists agreed that there is simply not enough relevant information to decide whether the benefits outweigh the negatives of fracking in the UK. There are several big questions that I think need to be answered. Just how much water would a UK shale gas well need? Do we have the technology to prevent water and air pollution? Do viable alternatives to fracking exist, and can we afford them?
Is there a perfect energy source? Should we stick to cheap-but-dirty coal or switch to inefficient bird-killing windmills? Are you more scared of nuclear meltdowns or global warming? As David Shukman concluded in his excellent BBC article, "whichever type of power you choose, it is going to make someone angry".
This blog is written by Sarah Jose, Biological Sciences, University of Bristol
You can follow Sarah on Twitter @JoseSci